U.S. patent application number 12/150570 was filed with the patent office on 2008-08-28 for pre-emptive power supply control system and method.
Invention is credited to Runsheng He, Sehat Sutardja.
Application Number | 20080209240 12/150570 |
Document ID | / |
Family ID | 32990424 |
Filed Date | 2008-08-28 |
United States Patent
Application |
20080209240 |
Kind Code |
A1 |
He; Runsheng ; et
al. |
August 28, 2008 |
Pre-emptive power supply control system and method
Abstract
A control system for controlling a power supply having an
operating function. The power supply to supply an output current to
an integrated circuit having at least one circuit block that is
controllable by an enable signal or a clock signal. A receiver to
receive the enable signal. A controller to determine a loading
status of the at least one circuit block as a function of the
enable signal or the clock signal and to control the output current
of the power supply as a function of the loading status of the at
least one circuit block such that the power supply preemptively
changes the output current.
Inventors: |
He; Runsheng; (Sunnyvale,
CA) ; Sutardja; Sehat; (Los Altos Hills, CA) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE P.L.C.
5445 CORPORATE DRIVE, SUITE 200
TROY
MI
48098
US
|
Family ID: |
32990424 |
Appl. No.: |
12/150570 |
Filed: |
April 29, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10426745 |
Apr 30, 2003 |
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12150570 |
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Current U.S.
Class: |
713/300 |
Current CPC
Class: |
G05F 5/00 20130101; H02M
2001/0019 20130101 |
Class at
Publication: |
713/300 |
International
Class: |
G06F 1/26 20060101
G06F001/26 |
Claims
1. A control system for controlling a power supply having an
operating function, the power supply to supply an output current to
an integrated circuit having at least one circuit block, the at
least one circuit block controlled in response to an enable signal,
comprising: a receiver to receive the enable signal; and a
controller to determine a loading status of the at least one
circuit block as a function of the enable signal and to control the
output current of the power supply as a function of the loading
status of the at least one circuit block such that the power supply
pre-emptively changes the output current, wherein the at least one
circuit block receives and is controlled in response to the enable
signal.
2. The control system of claim 1 further comprising a clock signal
communicated to the at least one circuit block in response to the
enable signal.
3. The control system of claim 1 wherein the power supply has a
pulse width modulation operating frequency; and the controller
controls the pulse width modulation operating frequency of the
power supply to control the output current.
4. The control system of claim 1 wherein the power supply has a
pulse width modulation on-time; and the controller controls the
pulse width modulation on-time of the power supply to control the
output current.
5. The control system of claim 1 wherein the controller controls an
operating function of the power supply to control the output
current; and the operating function is selected from a group
consisting of operating modes, current limit thresholds, operating
frequency, quantity of parallel power switches, and transient
response.
6. The control system of claim 5 wherein the operating modes
include hysteretic mode, pulse-width modulated mode, energy saving
mode, and variable frequency mode.
7. The control system of claim 2 further comprising a memory to
store clock information corresponding to the enable signal and the
clock signal.
8. The control system of claim 1 wherein the enable signal is an
encoded signal; and further including a decoder to decode the
encoded signal.
9. The control system of claim 2 further comprising a weighting
circuit to generate a weighted signal as a function of at least one
of the enable signal and the clock signal, the weighted signal
including clock information corresponding to the circuit block.
10. The control system of claim 9 wherein the clock signal has a
frequency and the clock information is selected from the group
consisting of the frequency of the clock signal, an approximate
power load of the circuit block corresponding to the enable signal,
and an enable status of the enable signal.
11. The control system of claim 9 wherein the weighted signal is an
encoded weighted signal; and further including a decoder to decode
the encoded weighted signal.
12. The control system of claim 1 wherein the at least one circuit
block includes a plurality of circuit blocks; and the enable signal
includes a plurality of enable signals having a one-to-one
correspondence to the plurality of circuit blocks.
13. A method for controlling a power supply having an operating
function, the power supply to supply an output current to an
integrated circuit having at least one circuit block controlled in
response to an enable signal, comprising: receiving the enable
signal, the enable signal to indicate a loading status of the at
least one circuit block; determining the loading status of the at
least one circuit block as a function of the enable signal; and
controlling the output current of the power supply as a function of
the loading status of the at least one circuit block such that the
power supply pre-emptively changes the output current, wherein the
at least one circuit block receives and is controlled in response
to the enable signal.
14. The method of claim 13 further comprising communicating a clock
signal to the at least one circuit block based on the enable
signal.
15. The method of claim 13 wherein the power supply has a pulse
width modulation operating frequency; and controlling the pulse
width modulation operating frequency of the power supply to control
the output current.
16. The method of claim 13 wherein the power supply has a pulse
width modulation on-time; and controlling the pulse width
modulation on-time of the power supply to control the output
current.
17. The method of claim 13 further comprising controlling the
operating function of the power supply to control the output
current; and wherein the operating function is selected from a
group consisting of operating modes, current limit thresholds,
operating frequency, quantity of parallel power switches, and
transient response.
18. The method of claim 17 wherein the operating modes include
hysteretic mode, pulse-width modulated mode, energy saving mode,
and variable frequency mode.
19. The method of claim 16 further comprising retrieving clock
information corresponding to the enable signal and the clock
signal.
20. The method of claim 13 further including generating an encoded
signal based on the enable signal; and decoding the encoded
signal.
21. The method of claim 14 further including generating a weighted
signal based on the enable signal, the weighted signal including
clock information corresponding to the circuit block.
22. The method of claim 21 wherein the clock signal has a frequency
and the clock information is selected from the group consisting of
the frequency of the clock signal, an approximate power load of the
circuit block corresponding to the clock control signal, and an
enable status of each enable signal.
23. The method of claim 21 further comprising encoding the weighted
signal; and decoding the encoded weighted signal.
24. A method for controlling a power supply having an operating
function, the power supply to supply an output current to an
integrated circuit having at least one circuit block controlled in
response to at least one of an enable signal and a clock signal,
comprising: receiving the enable signal, the enable signal to
indicate a loading status of the at least one circuit block;
determining the loading status of the at least one circuit block as
a function of the enable signal; controlling the output current of
the power supply as a function of the loading status of the at
least one circuit block such that the power supply pre-emptively
changes the output current, wherein the at least one circuit block
receives and is controlled in response to the enable signal;
generating a weighted signal based on the enable signal, the
weighted signal including clock information corresponding to the
circuit block, wherein the at least one circuit block is a read
channel that controls an external read head; wherein the enable
signal is a read gate signal; and wherein the clock signal is a
read clock; and performing a read operation that controls said read
head as a function of the read gate signal and the read clock.
25. A control system for controlling a power supply having an
operating function, the power supply to supply an output current to
an integrated circuit having at least one circuit block controlled
in response to an enable signal, comprising: means for receiving
the enable signal, the enable signal to indicate a loading status
of the at least one circuit block; means for determining the
loading status of the at least one circuit block as a function of
the enable signal; and means for controlling the output current of
the power supply as a function of the loading status of the at
least one circuit block such that the power supply pre-emptively
changes the output current, wherein the at least one circuit block
receives and is controlled in response to the enable signal.
26. The control system of claim 25 further comprising communicating
a clock signal to the at least one circuit block based on the
enable signal.
27. The control system of claim 25 wherein the power supply has a
pulse width modulation operating frequency; and means for
controlling the pulse width modulation operating frequency of the
power supply to control the output current.
28. The control system of claim 25 wherein the power supply has a
pulse width modulation on-time; and means for controlling the pulse
width modulation on-time of the power supply to control the output
current.
29. The control system of claim 26 further comprising means for
controlling the operating function of the power supply to control
the output current; and wherein the operating function is selected
from a group consisting of operating modes, current limit
thresholds, operating frequency, quantity of parallel power
switches, and transient response.
30. The control system of claim 29 wherein the operating modes
include hysteretic mode, pulse-width modulated mode, energy saving
mode, and variable frequency mode.
31. The control system of claim 26 further comprising means for
retrieving clock information corresponding to the enable signal and
the clock signal.
32. The control system of claim 25 further including means for
generating an encoded signal based on the enable signal; and means
for decoding the encoded signal.
33. The control system of claim 26 further including means for
generating a weighted signal based on the enable signal.
34. The control system of claim 31 wherein the clock signal has a
frequency and the clock information is selected from the group
consisting of the frequency of the clock signal, an approximate
power load of the circuit block corresponding to the clock control
signal, and an enable status of each enable signal.
35. The control system of claim 33 further comprising means for
encoding the weighted signal; and further including means for
decoding the encoded weighted signal.
36. The control system of claim 25 wherein the at least one circuit
block includes a plurality of circuit blocks; and the enable signal
includes a plurality of enable signals having a one-to-one
correspondence to the plurality of circuit blocks.
37. A control system for controlling a power supply having an
operating function, the power supply to supply an output current to
an integrated circuit having at least one circuit block, the at
least one circuit block controlled in response to a clock signal,
comprising: a receiver to receive the clock signal; and a
controller to determine a loading status of the at least one
circuit block as a function of the clock signal and to control the
output current of the power supply as a function of the loading
status of the at least one circuit block such that the power supply
pre-emptively changes the output current, wherein the at least one
circuit block receives and is controlled in response to the clock
signal.
38. The control system of claim 37 wherein the clock signal has a
frequency; and the loading status of the at least one circuit block
is a function of the frequency of the clock signal.
39. The control system of claim 37 wherein the power supply has a
pulse width modulation operating frequency; and the controller
controls the pulse width modulation operating frequency of the
power supply to control the output current.
40. The control system of claim 37 wherein the power supply has a
pulse width modulation on-time; and the controller controls the
pulse width modulation on-time of the power supply to control the
output current.
41. The control system of claim 37 wherein the controller controls
an operating function of the power supply to control the output
current; and the operating function is selected from a group
consisting of operating modes, current limit thresholds, operating
frequency, quantity of parallel power switches, and transient
response.
42. The control system of claim 41 wherein the operating modes
include hysteretic mode, pulse-width modulated mode, energy saving
mode, and variable frequency mode.
43. The control system of claim 37 further comprising a memory to
store clock information corresponding to the clock signal.
44. The control system of claim 37 further including a decoder to
decode an encoded signal, the encoded signal including the clock
signal and clock information corresponding to the clock signal.
45. The control system of claim 37 wherein the controller is a
central processing unit (CPU); and wherein the CPU generates a
weighted signal as a function of the clock signal and clock
information corresponding to the clock signal.
46. The control system of claim 45 wherein the clock signal has a
frequency and the clock information is selected from the group
consisting of the frequency of the clock signal and an approximate
power load of the circuit block corresponding to the clock
signal.
47. The control system of claim 45 wherein the weighted signal is
an encoded weighted signal; and further including a decoder to
decode the encoded weighted signal.
48. The control system of claim 37 wherein the at least one circuit
block includes a plurality of circuit blocks; and the clock signal
includes a plurality of clock signals having a one-to-one
correspondence to the plurality of circuit blocks.
49. A method for controlling a power supply having an operating
function, the power supply to supply an output current to an
integrated circuit having at least one circuit block controlled in
response to a clock signal, comprising: receiving the clock signal,
the clock signal to indicate a loading status of the at least one
circuit block; determining the loading status of the at least one
circuit block as a function of the clock signal; and controlling
the output current of the power supply as a function of the loading
status of the at least one circuit block such that the power supply
pre-emptively changes the output current, wherein the at least one
circuit block receives and is controlled in response to the clock
signal.
50. The method of claim 49 wherein the clock signal has a
frequency; and the loading status of the at least one circuit block
is a function of the frequency of the clock signal.
51. The method of claim 49 wherein the power supply has a pulse
width modulation operating frequency; and controlling the pulse
width modulation operating frequency of the power supply to control
the output current.
52. The method of claim 49 wherein the power supply has a pulse
width modulation on-time; and controlling the pulse width
modulation on-time of the power supply to control the output
current.
53. The method of claim 49 further comprising controlling the
operating function of the power supply to control the output
current; and wherein the operating function is selected from a
group consisting of operating modes, current limit thresholds,
operating frequency, quantity of parallel power switches, and
transient response.
54. The method of claim 53 wherein the operating modes include
hysteretic mode, pulse-width modulated mode, energy saving mode,
and variable frequency mode.
55. The method of claim 52 further comprising retrieving clock
information corresponding to the at least one circuit block.
56. The method of claim 49 further including decoding an encoded
signal, the encoded signal including the clock signal and clock
information corresponding to the at least one circuit block.
57. The method of claim 50 further including generating a weighted
signal based on the clock signal, the weighted signal including
clock information corresponding to the at least one circuit
block.
58. The method of claim 57 wherein the clock signal has a frequency
and the clock information is selected from the group consisting of
the frequency of the clock signal and an approximate power load of
the circuit block corresponding to the clock signal.
59. The method of claim 57 further comprising encoding the weighted
signal; and decoding the encoded weighted signal.
60. A control system for controlling a power supply having an
operating function, the power supply to supply an output current to
an integrated circuit having at least one circuit block controlled
in response to a clock signal, comprising: means for receiving the
clock signal, the clock signal to indicate a loading status of the
at least one circuit block; means for determining the loading
status of the at least one circuit block as a function of the clock
signal; and means for controlling the output current of the power
supply as a function of the loading status of the at least one
circuit block such that the power supply preemptively changes the
output current, wherein the at least one circuit block receives and
is controlled in response to the clock signal.
61. The control system of claim 60 wherein the clock signal has a
frequency; and the loading status of the at least one circuit block
is a function of the frequency of the clock signal.
62. The control system of claim 60 wherein the power supply has a
pulse width modulation operating frequency; and means for
controlling the pulse width modulation operating frequency of the
power supply to control the output current.
63. The control system of claim 60 wherein the power supply has a
pulse width modulation on-time; and means for controlling the pulse
width modulation on-time of the power supply to control the output
current.
64. The control system of claim 61 further comprising means for
controlling the operating function of the power supply to control
the output current; and wherein the operating function is selected
from a group consisting of operating modes, current limit
thresholds, operating frequency, quantity of parallel power
switches, and transient response.
65. The control system of claim 64 wherein the operating modes
include hysteretic mode, pulse-width modulated mode, energy saving
mode, and variable frequency mode.
66. The control system of claim 61 further comprising means for
retrieving clock information corresponding to the clock signal.
67. The control system of claim 60 further including means for
decoding an encoded signal, the encoded signal including the clock
signal and clock information corresponding to the clock signal.
68. The control system of claim 61 further including means for
generating a weighted signal based on the clock signal, the
weighted signal including clock information corresponding to the
circuit block.
69. The control system of claim 68 wherein the clock signal has a
frequency and the clock information is selected from the group
consisting of the frequency of the clock signal and an approximate
power load of the circuit block corresponding to the clock control
signal.
70. The control system of claim 68 further comprising means for
encoding the weighted signal; and means for decoding the encoded
weighted signal.
71. The control system of claim 60 wherein the at least one circuit
block includes a plurality of circuit blocks; and the clock signal
includes a plurality of clock signals having a one-to-one
correspondence to the plurality of circuit blocks.
72. The method of claim 13 further including generating the output
current through at least two parallel drive sections.
73. The control system of claim 25 wherein the power supply
includes at least two parallel means for generating the output
current.
74. The method of claim 49 further including generating the output
current through at least two parallel drive sections.
75. The control system of claim 60 wherein the power supply
includes at least two parallel means for generating the output
current.
76. The control system of claim 9 wherein the weighting circuit is
selected from a group consisting of processors, summers, and
look-up tables.
77. The control system of claim 1 wherein the power supply includes
at least two drive sections to supply the output current.
78. The control system of claim 77 wherein the controller controls
the drive sections.
79. The method of claim 21 further including providing a weighting
circuit for generating the weighted signal; and wherein the
weighting circuit is selected from a group consisting of
processors, summers, and look-up tables.
80. The method of claim 13 further comprising supplying the output
current through at least two drive sections.
81. The method of claim 80 further comprising controlling the at
least two drive sections as a function of the enable signal.
82. The control system of claim 33 wherein the means for generating
the weighting signal is selected from a group consisting of
processors, summers, and look-up tables.
83. The control system of claim 25 wherein the power supply
includes at least two means for supplying the output current.
84. The control system of claim 83 wherein the means for
controlling the output current controls the drive sections.
85. The control system of claim 45 wherein the weighting circuit is
selected from a group consisting of processors, summers, and
look-up tables.
86. The control system of claim 37 wherein the power supply
includes at least two drive sections to supply the output
current.
87. The control system of claim 86 wherein the controller controls
the drive sections.
88. The method of claim 57 further including providing a weighting
circuit for generating the weighted signal; and wherein the
weighting circuit is selected from a group consisting of
processors, summers, and look-up tables.
89. The method of claim 49 further comprising supplying the output
current through at least two drive sections.
90. The method of claim 89 further comprising controlling the at
least two drive sections as a function of an enable signal.
91. The control system of claim 68 wherein the means for generating
the weighting signal is selected from a group consisting of
processors, summers, and look-up tables.
92. The control system of claim 60 wherein the power supply
includes at least two means for supplying the output current.
93. The control system of claim 92 wherein the means for
controlling the output current controls the drive sections.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 10/426,745 filed on Apr. 30, 2003. The
disclosure of the above application is incorporated herein by
reference in its entirety.
TECHNICAL FIELD
[0002] An aspect of this invention relates to communication systems
for power supplies.
BACKGROUND
[0003] A power supply is typically used to convert unregulated
power from an input source to regulated power that is usable by
electronic equipment associated with the power supply. In some
types of electronic equipment such as portable computers, reduced
power consumption is of vital importance. To reduce power
consumption, a power management scheme may be employed to disable
and enable selected assemblies of the equipment during
predetermined operating modes. When the selected equipment
assemblies are enabled or disabled, the load presented by the
electronic equipment may change causing voltage transients in the
regulated power. During the transient loading condition, the
operation of the power supply typically deviates from optimal
operation such as decreased power efficiency, increased output
voltage regulation error, and potential transient overcurrents. The
power supply volume required for output filtering is typically
related to the magnitude of transient output overcurrents so that
for greater transient currents, increased volume is required for
output capacitors. In addition, transients in the regulated power
may adversely affect the operation of the electronic equipment,
decreasing reliability and potentially causing data errors and
automatic reset of the equipment.
SUMMARY
[0004] A control system for controlling a power supply having an
operating function. The power supply to supply output current to an
integrated circuit having at least one circuit block that is
controllable by an enable signal or a clock signal. A receiver to
receive the enable signal or the clock signal. A controller to
determine a loading status of the at least one circuit block as a
function of the enable signal or the clock signal and to control
the output current of the power supply as a function of the loading
status of the at least one circuit block such that the power supply
pre-emptily changes the output current.
[0005] The details of one or more embodiments of the invention are
set forth in the accompanying drawings and the description below.
Other features, objects, and advantages of the invention will be
apparent from the description and drawings, and from the
claims.
DESCRIPTION OF DRAWINGS
[0006] FIG. 1 shows a block diagram of an aspect of a control
system.
[0007] FIG. 2 shows a block diagram of another aspect of a control
system.
[0008] FIG. 3 shows a block diagram of a third aspect of a control
system.
[0009] FIG. 4 shows a flow diagram of an aspect of a control
system.
[0010] FIG. 5 shows a block diagram of an aspect of a control
system.
[0011] FIG. 6 shows waveforms associated with an aspect of a
control system.
[0012] FIG. 7 shows a block diagram of an aspect of a power
supply.
[0013] Like reference symbols in the various drawings indicate like
elements.
DETAILED DESCRIPTION
[0014] FIG. 1 shows an integrated circuit 10 for processing
information and a power supply 16 for supplying power to the
integrated circuit 10. The integrated circuit 10 may include a
power management scheme to control the operation of one or more
circuit blocks 12 of the integrated circuit 10. Advantageously,
operating functions of the power supply 16 may be controlled on the
basis of which of the circuit blocks 12 of the integrated circuit
10 are enabled or disabled.
[0015] In one exemplary power management scheme for the integrated
circuit 10, clock signals, CLK, and enable signals, ENB, associated
with each of the circuit blocks 12 may control operations of the
circuit blocks 12. Each of the circuit blocks 12 may be
individually controlled by the clock and enable signals. For
example, the enable signal, ENB, may control one of the circuit
blocks 12 independent of the clock signal, CLK. Also, the clock
signal, CLK, may control one the circuit blocks 12 independent of
the enable signal, ENB. In another aspect, an enable signal may
control the clock signal for one of the circuit blocks 12.
Disabling one of the circuit blocks 12 via the enable or clock
signals may cause an interruption of information processing within
the circuit block 12, resulting in a reduction in the power
consumption. The load presented by each of the circuit blocks 12
may be a function of the enable and clock signals. When a circuit
block 12 is enabled, the loading of the circuit block 12 may be
greater than when the circuit block is disabled. Similarly, when a
circuit block 12 receives an active clock signal, the loading of
the circuit block 12 may be greater than when the circuit block 12
receives an inactive clock signal or when the frequency of the
clock signal is lower. While the circuit blocks 12 are shown and
described as being portions of a single integrated circuit, the
particular grouping is merely exemplary. For example, each of the
circuit blocks 12 may be included in separate integrated
circuits.
[0016] In another aspect, clock control circuits may be included
within the circuit blocks 12 to control the operation of the
corresponding clock signals. The clock control circuits may each
receive a clock signal and a clock enable signal. The clock signal
may be controlled as a function of the clock enable signal.
[0017] A power supply 16 may generate one or more regulated outputs
to power the circuit blocks 12. The power supply 12 may be any type
of regulator such as linear regulators and switching regulators.
The power supply 16 may include numerous operating functions such
as operating frequency, operating mode, current limit thresholds,
the quantity of parallel power switches that conduct energy between
the input power source and the output, and control circuitry. The
control circuitry may include the modules and components that shape
the response of the power supply to steady-state and transient
operating conditions. The control circuitry may be implemented in
digital circuitry, analog circuitry, or mixed-signal circuitry.
[0018] The power supply 16 may include a control system 18 to
control the operating functions of the power supply as a function
of the circuit blocks 12 that are enabled. While the control system
18 is shown and described as being included in the power supply 16,
the described implementation of the control system 18 is merely
exemplary, and the entire control system 18 as well as portions of
the control system 18 may be located external to the power
supply.
[0019] The control system 18 may include a receiver 20 to receive
the clock and enable signals. The receiver 20 may be any type of
receiver such as buffers, amplifiers, passive, and active circuits,
and extending to a mere conductive path. The receiver 20 may
receive any type of clock control signal that is indicative of the
current loading status of the circuit blocks 12 such as clock
signals and enable signals. The clock control signal may control
operations such as read operations and write operations of the
circuit block 12. The current loading status of the circuit block
12 may be determined based on the clock control signal such as read
operations at a predetermined rate of one circuit block 12 may
correspond to a predetermined current loading of the circuit block
12. A controller 22 may be in communication with the receiver 20 to
receive the loading information. The controller 22 may control some
or all of the operating functions of the power supply 16 in
response to the loading information. For example, in response to
detecting that the clock for one of the circuit blocks 12 is being
enabled, the controller 22 may change the operating mode of the
power supply 16 to a hysteretic mode to speed up the transient
response of Vout.
[0020] FIG. 2 shows an aspect of a control system 50 to control the
operating functions of a power supply 52 as a function of the
loading presented by an integrated circuit 54. The loading of the
integrated circuit 54 may vary based on portions of the integrated
circuit 54 that receive clock signals that are controlled by clock
enable signals, CES, 55. There may be any quantity of clock enable
signals 55 controlling different portions of the integrated circuit
54.
[0021] The control system 50 may include an encoder 56 to combine
clock information related to multiple clock enable signals 55 into
an encoded signal. The encoded clock signal may include clock
information such as the enable status of each clock enable signal
and the approximate power load corresponding to each clock enable
signal. Any type of encoder 56 may be employed for encoding the
clock enable signals 55 into a combined signal.
[0022] A decoder 58 may decode the encoded signal to extract the
clock information related to the clock enable signals 55. Any type
of decoder may be employed to decode the encoded signal. A clock
signal 59 may be communicated to the encoder 56 and decoder 58 for
encoding and decoding the clock information related to the clock
enable signal signals 55. The decoder 58 may communicate the clock
information to a controller 60.
[0023] A controller 60 may receive the clock information from the
decoder 58 and control the operating functions of the power supply
52 on the basis of the clock information. The controller 60 may
also access a memory 62 containing loading information related to
the integrated circuit 54. The memory 62 may be structured so that
the loading information is accessed as a function of the clock
enable signals 55. The loading information may include information
such as the approximate power load corresponding to each clock
enable signal and the load profile corresponding to each clock
enable signal. For example, if the decoded clock information
indicates that CES2 is enabled, the controller 60 may access the
memory 62 to determine the approximate power load corresponding to
CES2.
[0024] While the control system 50 is shown and described as being
separated into multiple assemblies, the particular division of
functions is merely exemplary, and the control system 50 could be
mounted on a single assembly or multiple assemblies. In one
exemplary aspect, the encoder 56 may be included in the integrated
circuit 54, and the decoder 58, controller 60, and memory 62 may be
included in the power supply 52. In another exemplary aspect, the
encoder 56 is included in the integrated circuit 54, and the
controller 60 is included in the power supply 52, while the decoder
58 is a separate assembly.
[0025] FIG. 3 shows an aspect of a control system 100 to control
the operating functions of a power supply 102 as a function of the
loading presented by an integrated circuit, IC, 104. The IC 104 may
receive several control signals, CNTL, 108 such as enable signals,
clock enable signals, and clock signals that may affect the power
loading of portions of the IC 104 by controlling the operation of
those portions of the IC 104. The control signals 108 may also be
communicated to a weighting circuit 110 so that the weighting
circuit 110 may combine the control signals 108 into a combined
signal. The weighting circuit 110 may apply weighting to groups of
the control signals 108 such as indicating whether more than half
of the total quantity of control signals in a group are enabled or
active. In such a case, the combined signal may request a change to
the operating functions of the power supply 102. The weighting
circuit 110 may also apply weighting to each control signal on the
basis of the predicted loading change associated with the portions
of the IC 104 corresponding to each of the control signals 108.
Loading information for applying the weighting may be stored in any
device such as a look-up table and a database. The weighting
circuit may be implemented in any device or combination of devices
such as processors, summers, and lookup tables. The weighting
circuit 110 may also encode the combined signal.
[0026] A controller 106 may control the operating functions of the
power supply 102 as a function of the combined signal. The
controller 106 may be located with the power supply 102 as well as
external to the power supply 102.
[0027] In one exemplary aspect, the weighting circuit 110 may be
formed as a portion of the IC 104 to form a single integrated
circuit (IC) 112 and the controller 106 may be combined with the
power supply 102 into a combined power supply 114. By forming the
weighting circuit 110 on the same IC 112 as the circuitry of the IC
104, an interface 116 to the power supply 114 is reduced. The
weighting circuit 110 may combine multiple clock and enable signals
into a weighted signal that may be communicated to the combined
power supply through the interface 116. The weighted signal may be
a digital signal having a bitlength of two or more bits to indicate
the expected change in load current from the IC 112. The greater
the bitlength, the greater the resolution of the weighting
signal.
[0028] FIG. 4 shows an aspect of the operation of a control system
for controlling the operating functions of a power supply that
supplies power to an integrated circuit, IC. At step 200, the clock
and/or enable signals may be communicated to an integrated circuit
to control portions of the integrated circuit. At step 201, the
clock and/or enable signals may be received. At step 202, weighting
may be applied to the clock and/or enable signals to indicate a
loading change of the portions of the integrated circuit. At step
204, the clock and/or enable signals may be combined into a
combined signal. At step 206, the combined signal may be encoded.
At step 208, the encoded signal may be communicated. At step 210,
the encoded signal may be received. At step 212, the encoded signal
may be decoded. At step 214, control the operating functions of the
power supply as a function of the decoded signal.
[0029] FIG. 5 shows an aspect of a control system 308 to control
the operating functions of a power supply 302 as a function of the
loading presented by one or more read channels 304. The read
channels 304 may receive one or more read signals, RG, for
controlling read operations by the read channels 304 of one or more
read heads 306. The read heads 306 may be included in a disk drive
unit and read information stored in the disk drive unit. The power
load presented by the read channels 304 and read heads 306 to the
power supply 302 generally increases during a read operation. The
power load presented by the read operations may include any range
of power load such as no power, intermediate power, and full power.
The control system 308 may be implemented in any type of circuit
such as processors and discrete circuits. The control system 308
may determine the loading status of each read channel 304 on the
basis of the read signals and generate a power supply control
signal to preemptively control the output current of the power
supply before a change occurs in the output current of the read
channel 304.
[0030] The read signals may be any type of signal that controls
read operations of the read channels 304 such as read enable
signals and read clock signals. Any combination of read signals may
control the read channels 304 such as each may control a
corresponding read channel 304, and a single read enable signal may
control several of the read channels 304.
[0031] Referring to FIG. 6, a first waveform shows a read enable
signal 310, RG, transitioning from "off" to "read" to "off". A
second waveform shows a read clock signal 312, READ CLK, for
controlling the read channel 304. The read enable signal may
control the operation of the read clock signal such as by
controlling the operating frequency of the read clock signal to
control read operations of the read channel 304. A higher operating
frequency of the read clock signal may cause more read operations
per unit of time causing an increase in the power load presented by
the read channel. The read clock signal may also control the read
channel without a read enable signal. For example, a clock
generator (not shown) may control the operating frequency of the
read clock signal to control the read channel 304 read operations.
A third waveform shows a current load 314, I.sub.LOAD, presented by
the read channel 304. The current load 314 may increase as the
frequency of read operations increases. A fourth waveform shows an
output current 316, I.sub.OUT, of the power supply 302 for
supplying power to the read channel 304. A fifth waveform shows a
speed signal, SPD, 317 to control the speed of the read operations
such as by changing the frequency of the read clock 312. A sixth
waveform shows a pulse width modulation (PWM) signal 319 of an
exemplary power supply. The control system 308 may extend the
on-time 319a or off-time 319b of the PWM signal 319 to improve the
response time of the power supply to expected load transients.
[0032] In one aspect of a read operation, the read enable signal
310 is initially low disabling the read clock signal 312. When the
read enable transitions high the read clock signals 312 are
enabled. The read channels 304 start a read operation when the read
clock signals become active. The read clock signals are also
communicated to the control system 308 which determines an
estimated change in the current load of the power supply based on
the read signals that are enabled and the number of read operations
that will be executed per unit of time. The control system 308 may
communicate the change in the current load to the power supply 302
which then changes the output current 316 to match the expected
change in the load current 314 to pre-empt the occurrence of
transients in the output voltage.
[0033] The read operations continue at about a constant frequency
until switching instant 318 when the frequency of the read
operations decreases. The control system 308 senses the change in
the read clock signal 312 and signals the power supply 302 to
pre-emptively change the output current 316 to anticipate the
expected change in the load current 314. The change in output
current 316 approximately matches the change in the load current
314 thereby reducing voltage transients and stress on filter
elements such as energy storage capacitors.
[0034] FIG. 7 shows an aspect of a power section 320 of the power
supply 302. The power section 320 may include one or more drive
sections 322 for converting an input voltage to a chopped output.
Each of the drive sections 322 may connect through an inductor 324
to an output capacitor 326 for filtering the chopped output to a
regulated output.
[0035] A controller, CNTRLR, 328 may control each of the drive
sections 322 individually in response to enable and clock signals.
The controller 328 may receive and process the enable and clock
signals in accordance with the principles of the controllers and
weighting circuits described in this specification. The controller
328 may, in response to the enable and clock signals, set each of
the drive sections 322 to generate any proportion of the total
output current required by the portions of the integrated circuit
or integrated circuits. For example, equal portions of the output
current may be generated by each of the drive sections 322. In
another example, one drive section 322 may generate all of the
output current while the remaining drive sections 322 generate no
output current.
[0036] A number of embodiments of the invention have been
described. Nevertheless, it will be understood that various
modifications may be made without departing from the spirit and
scope of the invention. Accordingly, other embodiments are within
the scope of the following claims.
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